1. Field of the Invention
The present invention relates to a paste dispenser and a method for controlling the same, and more particularly, to a paste dispenser and a method for controlling the same having a nozzle position compensating device, in order to accurately compensate or correct the position of a newly exchanged nozzle, when the nozzle is exchanged in the paste dispenser.
2. Discussion of the Related Art
Generally, a paste dispenser is a device used to dispense various types of paste, such as a resistive paste and a sealing paste, on a substrate in a set form, in other words, a desired pattern.
The paste dispenser consists of a stage on which a substrate is mounted, and a head unit having a nozzle for dispensing the paste on the substrate. Herein, the head unit includes a paste container accommodating the paste therein, and a nozzle connected to the paste container and dispensing the paste on the substrate. When dispensing a paste pattern on a substrate, the relative position between the substrate and the nozzle is changed, and thus a desired paste pattern is formed on the substrate.
Meanwhile, when the paste within the paste container is exhausted, the used paste container and nozzle are newly replaced (hereinafter collectively referred to as “nozzle exchange”). Also, when the paste pattern is completely formed on a first substrate, generally, the paste container and the nozzle are newly replaced, so as to form paste patterns on a second substrate.
When exchanging the nozzle, due to the fabrication accuracy of the nozzle or the paste container, the assembly accuracy between the nozzle and the paste container, and so on, the relative position of the nozzle (more specifically, an outlet of the nozzle) to the substrate is altered before and after the nozzle exchange. Since the paste pattern on a substrate must be accurately formed, the position of the exchange nozzle should be compensated or corrected.
The method of compensating the position of the exchanged nozzle is disclosed in the Korean Patent Application No. 10-1997-0003540. According to the above-referenced application, in order to compensate the nozzle position, a dummy substrate for correcting a nozzle is mounted on a stage. Then, the paste is dispensed on the substrate in the form of a plurality of dots or in linear forms crossing over one another. The position of the dispensed paste pattern is measured by an image sensing camera, so as to compensate the position of the exchange nozzle. When the compensation is completed, a real substrate (i.e., an actually used substrate) is used to form a desired paste pattern.
However, the above-described related art paste dispenser has the following disadvantages.
The actually dispensed paste on the dummy substrate is measured, so as to compensate the position of the exchanged nozzle. In other words, in the related art, the dummy substrate should be detachably fixed to the stage, and the paste should be dispensed on the dummy substrate. Therefore, surplus time is consumed for this compensating process, which has no relation with the actual process of dispensing the paste to the real substrate.
Also, in the related art, since the paste should be actually dispensed on the dummy substrate, the fabrication cost is increased.
Finally, the position of the nozzle is not directly compensated. In other words, since the dispensed paste is used instead of an exchanged nozzle, the position of the nozzle is indirectly compensated, and thus the accuracy in compensating the nozzle position is reduced.